Book Review

POMEGRANATES: Ancient Roots to Modern Medicine
Vol. 43 of Medicinal and Aromatic Plants—Industrial Profiles

by Navindra Seeram, Risa N. Schulman and David Heber

Boca Raton, Florida: Taylor and Francis CRC Press, 2006,
244 pp, index, ISBN-08493-9812-6, hardcover $129.95.
Website: www.crcpress.com
(Price/availability info may have changed since original publication of review.)

Reviewed by Dr. John M. Riddle (1/2007)

The pomegranate—literally the “grained apple”—has received considerable scientific attention in the last decade; persuasively this study indicates that our interest in it is justified. Forty-nine contributors from laboratories in the United States (concentrating in California), Israel, Canada, Spain and India examined most aspects of the pomegranates’ chemistry, health effects (including hormonal and antimicrobial properties), commercialization and horticultural aspects (growth and postharvest biology). As one of the earliest domesticated fruit plants (probably from its indigenous regions in present-day Iran or Turkey or trans-Caucasus regions), ancient Mesopotamian and Indus-valley populations revered the pomegranate both as a food and medicine. It was not introduced to Egypt until the Middle Kingdom. Most of these studies are laboratory, in vitro and in vivo, studies carefully crafted and judiciously concluded to present to the modern public the importance the pomegranate can bestow on health regimens and, in a few cases, therapeutics.

All parts of the small tree were subjected to mass spectrometric analysis and many molecular structures are identified and diagrammed. Commercial pomegranate juice, made from the whole plant, reveals antioxidant capacities three times higher than that of red wine or green tea. All tree parts possess antioxidant activities but most powerful were the pomegranate’s tannins from bark and stem. Also some studies indicate that this plant has strong anticarcinogenic properties for oral, colon and prostate cancer cell inhibitions. Additionally, whole pomegranate has three active flavonoids that stimulate production of estrogen, a natural steroid, in actions perhaps similar to soy and licorice. Pomegranate seed beneficially treats diarrhea, and an extract from its peel promotes wound healing. It is not enough to identify the chemical agents per se, but also to investigate the pomegranate’s bioavailability and metabolism—which one study did, primarily with rat populations. Pathways are explored; in rat populations, no toxic effects were found in liver or kidney damage when high oral dosages of pomegranate punicalagin, a pharmacological compound, were administered.

Punicalagin is responsible for the potent antioxidant effects to minimize low-density lipoprotein (LDL) cholesterol and, as a bonus, to inhibit arteriosclerosis in mice and humans. The antioxidants lessen hypertension. One study presents a helpful diagram showing the major pathways by which pomegranate polyphenols reduce macrophage formation associated with advanced arteriosclerosis. Studies with rats show that dietary intake of pomegranate juice reduces ischemic strokes, presumably by improved vascular function. A person who believes that this book is too enthusiastic about pomegranate should go to Medline, www. medline.com, to see the attention modern investigators are paying to its medicinal use in cancer research (key words: pomegranate [Punica granatum] and cancer). Some studies indicate a beneficial application for human breast cancer; most attention in pomegranate therapeutic applications concentrates on aggressive human prostate cancer by hypothesizing that the cholesterol homeostasis breaks down in the organ with aging and contributes to the induction of malignancy. A separate study by an Indian team explores the pomegranate’s chemical constituents for dietary interruption of cell proliferation and differentiation in cancer prevention notably for skin, lung and prostate cancers. While the research is promising, these researchers enter a call for more research. In line with this call, two California investigators followed human trials of pomegranate juice and concluded that it is “a promising chemopreventive strategy” (p. 139) and a “novel therapeutic agent” for patients with prostate cancer.

The last four biochemistry studies explore the traditional use of pomegranate for its estrogenic qualities (fertility enhancers and inhibitors and hormonal effects) and its antimicrobial activities. Conclusions of one study were carefully guarded, since the pomegranate’s pathways as a food and dietary supplement are yet to reach definitive results; the study’s research, however, is promising in its chemical identifications and pathway hypotheses. Another human trial study of women ingesting pomegranate juice intake for one week recorded a“significant increase in the production of estrone, a form of estrogen, in postmenopausal women. This study called for a longer-term determination of a cumulative effect because only a single week of ingestion was measured. Since phytoestrogens probably reduced the risk of cardiovascular diseases, endocrine-related cancers and hot flashes, more research is clearly indicated. The study covers the antimicrobial activities of pomegranate with the specific pathogens that could be promising for antifungal, antiviral and antidiarrheal disorders.

The last two sections cover commercialization and horticultural aspects (botanical perspectives and postharvest technology). The chapter on commercialization delves into the pomegranate’s history more thoroughly than the previous chapters; included in this section is a useful catalogue of suppliers (including websites) and how each prepares the pomegranate products for sale. The final study is a broad review of the cultural conditions for its growth, genetic diversity and a listing of germplasm collections worldwide that point to overcoming some obstacles to wider distribution of pomegranate- growing regions and better varieties. Factors affecting the quality and safety of pomegranate products conclude this study.

This volume should be celebrated as the thorough review of the state of science about a single plant. Strangely, given the subtitle,“ancient roots to modern medicine,” the least reviewed aspect is the pomegranate’s historical use. Its biochemistry, therapeutics, nutritional and horticultural dimensions compensate for this minor deficiency. The ancients knew well what we are rediscovering; the pomegranate is one of nature’s greatest fruit plants. So let us toast these investigators for their talented scholarship with a pomegranate martini—but hold the gin!

© Copyright 2007, California Rare Fruit Growers, Inc.
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